DESCRIPTION (Applicant's Description) A major aspect of cellular signaling involves the identification and characterization of molecules that transmit signals from the cell surface to the nucleus in response to hormones, light, odorants and growth factors among many other extracellular signals. The recent elucidation of the three dimensional structure of several of the molecules involves in signal transduction has been particularly valuable in these efforts. In this meeting, lectures will be presented to cover various mechanisms by which signals are transmitted across the plasma membrane via the cytoplasm to the cell nucleus. Emphasis will be placed on G-protein and receptor tyrosine kinase systems. In addition, a variety of mutations that occur in signaling molecules lead to variety of disease and detailed understanding of the associated pathways and their control mechanisms should enhance the development of novel drugs and treatments. Several pathologies that have been related to cell signaling abnormalities will be discussed.